3D TVs - I didn't notice as many 3D tvs displayed with prominent demo stations in front of electronic shops during a recent trip compared to a few years ago. Have you searched for 3D TV blogs in Japanese?

Akiba's gone very Anime and Manga oriented over the last decade or so. I'm sure there are still hardware component shops but there are also a lot of maid cafes. Just want to put this upfront as it is quite different from the tech amazement and awe one would get a decade or two ago if you're used to a big US city and gadget nerd.

My favorite electronic one stop electronics shop is Yodobashi Akiba. If you want to see some items which will never make it the the US - check out the beauty electronics section. There are several beauty gadgets made for the domestic market like sonic skin toning machines, nano facial steamer, and heated mascara curlers. Some of the other household goods like mini clothing steamer iron and a machine which grinds tea leaves and brews tea (similar to the fancy IoT coffee machines in the US) are "only in Japan" items in small appliance home goods section. The advanced massage chairs are fun for button mashing.

As for tech gadgets to buy - check out the power cords section. Elecom, Panasonic, Sanwa, and Yazawa have thoughtfully produced rotating power taps and extensions. Immensely useful gadgets to carry when traveling.

There are some good headphone stores and displays, too. I've never seen as much headphone variety in a US electronics/audio store http://www.digitalaudioreview.net/20...hone-retailer/